Combined reamer and tap



Nov. 27, 1923 1,475,561

. J. BATH ET AL COMBNED REAMER ND TAP Filed April 27, 1921 Patented Nov.27, 1923.

UNI-TED STATES .PATENT OFFICE.I

JOHN BATH AND HARRY F. CLIFFORD, OF WORCESTER, MASSACHUSETTS; SAID(.'ILIF- g FOBD ASSIGNOR T0 SAID BATH.

COMBINED BEAMER AND TAP.

Application filed A .pril 27,4921. Serial No. 464,806.

To all whom t may concern.'

Be it lmown that we, JOHN BATHl and HARRY F. CLIFFORD, citizens of theUmted -States, both residing at Worcester, in the county of Worcesterand. State of Massachusetts, have invented a new and useful CombinedReamer and Tap, of which the following is aspecification.

This inventlon relates to a combination tool comprising 1n a single unita reamer and a finishing tap. It is the object of our inone importantyfeature of'our invention re-v lates to the provision of a combinedreamer andltap so constructed thatthe reamer w1ll remove the roughingburrs and bring the hole accuratelyA to finished size before thefinishin tap enters the thread, V

In or er that the reamermay accurately i perform its functions, we findit also desir'- able to provide for the accurate centering of the reamerand for this 'purpose a further feature of our invention relates to theprovision of a threaded pilot which willv enter and follow the rough tapd thread and which will not bediverte y the burrs left in the hole.

.Further features of' our inventiorrfrelate to combinations of partswhich will be hereinafter described and more particularly pointed out inthe appended claim.v

A'preferred form of the invention and modifications therein are shown inthe' drawings in which Fig. 1 is a side ,elevation of our improvedtapand reamer; Y

Fig. 2 is, a partial longitudinal section thereof; and

cation.

Fig. 3""is a part1al elevation of amodifi- Referring to Figs. 1 and 2,we have shown a combined reamer and tap comprising a threaded pilot 10,va reamer4 11 and a finish- Aing tap 12 together with the usual extension13 to which a wrench orhandle may be applied. The reameris grooved orfluted longitudinally and the rea-mer blades and the teeth of thefinishing tap 12 are backed off to provide clearance in the usualmanner. The threaded pilot 10, however, is not commonly relieved orbacked ofi,'as the teeth have no cutting function but' are formed theright size to enter the rough tapped hole as shown in Fig. 2 and alignthe reamer and finish-V ing tap with the thread already cut.

Reference to Fig. 2 will also show that the -burrs 14; raised by theroughing tap will enter between the teethof the pilot 10 and will thusnot divert the pilot from .its tion. I

The remuer-'11 is drawn into the holeby- Athe pilot 10"-, removing theburrs 14 and reaming the hole to its exact finished size, after whichthe finishing tap 12 makes the true posilight cut necessary to size thethread. VThe combined operation of the Vthreaded pilot,

the reamer and the finishing tap is found to` reduce unusually accurateresults.

n Fig. 3 `the threaded pilot is replaced by a .roughing tap 15 formed asa unit with a reamer 11* and finishing tap 12a. This form of ourinvention is useful where it is desirable to rough tap, ream and finisha thread at a single operation, although under usual conditions Weconsider it preferable to'lat- .tain the result by the use of twoseparate taps. When using this modified construction, the roughing` tap15 also serves as a threaded pilot for' the reamer 11 and finishing tap12a, the o eration of the latter'parts being substantial y the same aspreviously described.

Having thus described our invention it will be evident that changes andmodifications can be made therein by those skilled inthe art within thespirit and scope of our invention as setforthl in the claim, and we donot wish to be otherwise limited to the details herein disclosed butwhat We claim eeetive to ream the rough tapped threads is substantiallyto inished inner diameter and 10 A combined reamer and tap for threadingto remove burrs therefrom before the operaia cylindrical hole comprisinga threaded tion of the finishing tap.' i5 pilot fitting the threads of arough tapped In testimony whereof We have hereunto hole, a, finishingterp` for said straight rough aixed our signatures. tapped hole, end areemer inter osed be- JOHN BATH.

tween said pilot and seid'tep ,en of e size v HARRY F, CLHPFORD.

